1. Field of the Invention
The present invention relates to a stepless cutter feeding mechanism for a lathe to cut a workpiece at a constant linear cutting speed to thereby provide a product of good quality.
2. Description of the Related Art
A typical lathe for cutting, a workpiece (e.g., a shaft) generally includes a cutter feeding device that feeds a cutter transversely to process the shaft. It is known to keep the linear cutting speed during cutting of the workpiece so as to obtain a product of good quality. FIG. 8 of the drawings illustrates a typical cutting of a shaft 50 by a cutter 60 that is transversely fed at a constant speed. The linear cutting speed (the peripheral displacement per minute of the cutter along a circumference of the workpiece) is V1 when the shaft 50 is rotated through an angle .THETA.. Nevertheless, referring to FIG. 9, when the diameter D of the shaft 50 becomes smaller as a result of cutting, the linear cutting speed V2 is smaller than V1. Thus, the linear cutting speed for the shaft 50 is not constant such that the resultant shaft 50 has a poor quality.
The present invention is intended to provide a buckle device that mitigates and/or obviate the above problem.